1. Field of the Invention
The present invention relates to an improved process for producing acrylamide or methacrylamide utilizing microorganisms.
2. Description of the Prior Art
As a process for producing acrylamide or methacrylamide, there has heretofore been known a process of reacting acrylonitrile (AN) or methacrylonitrile (MAN) with water using reduced copper as a catalyst. However, it has been desired to develop a novel and industrially more advantageous process since the catalytic process involves a difficult catalyst preparation and regeneration, and the isolation and purification of the amide produced is onerous.
On the other hand, as a process for producing acrylamide or methacrylamide from acrylonitrile or methacrylonitrile utilizing an enzymatic reaction, an interesting process using bacteria belonging to the genus Bacillus, the genus Bacteridium in the sense of Prevot, the genus Micrococcus, the genus of Brevibacterium in the sense of Bergy, or the like has recently been proposed in U.S. Pat. No. 4,001,081. This process is merely based on the discovery that the above-described bacteria hydrolyze various organic nitriles to produce the corresponding organic acid amides. In the case of using acrylonitrile or methacrylonitrile (Examples 6-8 in the Patent) for example, the patent describes that acrylamide or methacrylamide was obtained almost quantitatively under the reaction conditions of: 8 to 12 wt % acrylonitrile or methacrylonitrile concentration, 2 to 4 wt % bacterial cell concentration, 7 to 9 in pH, 25.degree. C. in temperature and 20 to 30 minutes reaction time. It is true that acrylamide or methacrylamide can be produced at a concentration as high as 10 to 20 wt %, but the bacterial cells so rapidly lose their enzymatic activity under such conditions that it is almost impossible to use them repeatedly. In addition, the solution from which the bacterial cells are separated is colored an extremely dark yellow and contains various impurities originating from the cells, and hence an onerous purifying step is necessary. Thus, the abovedescribed process is not economically advantageous in industrial applications.